This invention relates generally to the monitoring of pipelines and, more particularly, to the monitoring of an in-ground pipeline for contact therewith.
In-ground pipelines have found various uses. For example and without unnecessary limitation, in-ground pipelines are used extensively in the transmission of various materials between selected points or locations. Natural gas is one example of a material frequently transmitted via in-ground pipelines.
It is known that damage to in-ground pipelines can occur directly as a result of acts of nature such as earthquakes and landslides, for example. The damage resulting to in-ground pipelines as a result of the occurrence of such acts typically occurs on a sufficiently large scale such that multiple pipe joints are affected and detection of the occurrence of such damage is relatively easy. Pipeline damage can, however, occur due to the act of a third party, i.e., a party other than the owner or operator of the pipeline. Such damage is known as xe2x80x9cthird-party damage.xe2x80x9d When the damage due to an act of a third party causes an immediate rupture of a pipe, little can be done via on-line monitoring to prevent an ensuing incident. However, many third-party contacts with pipelines can cause damage that does not result in an immediate pipeline failure but rather cause damage that may, with time, lead to a pipe failure such as in the form of a leak or a catastrophic rupture. For example, time and pressure cycling to which a pipeline might normally be subjected may, with time, eventually lead to the occurrence of such a pipeline failure, with such a pipeline failure sometimes referred to as a xe2x80x9cdelayed failure.xe2x80x9d In view of the above, the occurrence of such third-party contact and the effective detection thereof has proven to be a persistent problem While sounds associated with contact with a pipeline can be transmitted through the pipeline and detected at substantial distances from the point of contact via highly sensitive acoustic sensors, the high sensitivity of such sensors can produce or result in a significant number of false calls arising from sources other than by contact with the pipeline. For example, sources such as passing vehicles and weather conditions such as thunder and rain can produce or result in false calls to a normal sound detection and monitoring method and system.
In view of the consequences of the failure of an in-ground pipeline due to third-party contact, particularly when coupled with the extensive construction related with urban expansion and encroachment of the right-of-way commonly associated with many of such in-ground pipelines, there is a need and a demand for a method and system for monitoring in-ground pipelines and, in particular, detecting contact with a pipeline and proactively warn of the potential for the occurrence of damage associated therewith. In particular, there is a need and a demand for a monitoring method and system that can effectively eliminate false calls such as may arise from at least certain noncontact events. Further, there is a need and a demand for a monitoring method and system that can facilitate the speedy and accurate identification of the location on an in-ground pipeline whereat such a contact has occurred.
A general object of the invention is to provide an improved method and system for monitoring an in-ground pipeline.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part, through a specified method for monitoring an in-ground pipeline. In accordance with one preferred embodiment of the invention, such a method involves detecting an occurrence of a contact with an in-ground pipeline via an acoustic sensor employing a first selected detection parameter and a second sensor employing a second selected detection parameter which is selected detection parameter is different. The acoustic sensor and the second sensor each transmits a corresponding input signal to a processor whereat the input signals are appropriately processed to determine the point of contact with the in-ground pipeline.
In a specific form of such method, the acoustic sensor is at a first known location relative to the in-ground pipeline, in contact with the in-ground pipeline, and transmits a corresponding first input signal to a processor. The second sensor is at a second known location relative to the in-ground pipeline. The second sensor employs a second selected detection parameter and transmits a corresponding second input signal to the processor. The second selected detection parameter is different from the first selected detection parameter and the first and second input signals arrive at the processor at different times and at known respective speeds.
The prior art has generally failed to provide a method and system for the monitoring of an in-ground pipeline in a manner as effective as desired. In particular, the prior art has generally failed to provide a method and system for the monitoring of an in-ground pipeline in a sufficiently unintrusive and effective manner such as to permit the reliable detection of contact with the pipeline and proactively warn of the potential for the occurrence of damage associated with such contact.
The invention further comprehends a method for identifying a location at which an in-ground pipeline has been subject to a contact. In accordance with one preferred embodiment of the invention, such a method involves:
detecting an occurrence of a contact with the in-ground pipeline via an acoustic sensor at a known location relative to the in-ground pipeline, the acoustic sensor in contact with the in-ground pipeline and transmitting a corresponding first input signal to a processor;
detecting the occurrence of the contact with the in-ground pipeline via an impressed current sensor, the impressed current sensor at a location proximate to the known location of the acoustic sensor, the impressed current sensor transmitting a corresponding second input signal to the processor, wherein the first and second input signals arrive at the processor at different times and at known respective speeds; and
processing the first and second input signals in the processor to determine the location of the contact with the in-ground pipeline.
Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings.